Temperature-dependent mutual interference of adult mealybug destroyer, Cryptolaemus montrouzieri, feeding on citrus mealybug, Planococcus citri

Cryptoleamus montrouzieri is the most important natural enemy of Pseudococcus citri. The effects of different temperatures and different densities of C. montrouzieri on predation rate, searching efficacy and mutual interference of the mentioned coccinellid feeding on the nymphs of P. citri was studied. Hassel and Varley model was applied for estimation of interference constant. According to the ANOVA, per capita predation of the male and female coccinellids was not affected significantly by interaction of temperature and predator density, at 99% confidence level. Both, temperature and predator density had a significant effect on per capita predation rate of the coccinellids. The maximum and minimum predation rates of the males were 16.83 and 7.96 nymphs at 1 and 8 densities, respectively. On the other hand, the maximum and minimum per capita predation rates of the females were 24.17, and 9.59 nymphs at 1 and 8 densities, respectively. Results showed increasing densities of the coccinellids decreased per capita predation rate and decreased per capita searching efficacy. However, increasing temperature resulted in increase of per capita predation rate and per capita searching efficacy of the coccinellids. Finally, it is concluded that different temperatures and prey-predator ratios affect mutual interference of C. montrouzieri.